JPS61220182A - Tape guide for cassette tape - Google Patents

Abstract

PURPOSE:To set and run a tape light and smoothly by forming a tape guide for cassette tape with a composition consisting of 15-60wt% high polymer materials, 35-80wt% spherical inorganic filler of 0.5-1.0 Wadell spheroidicity, and 0-15wt% slidability giving agent. CONSTITUTION:The tape guide for cassette tape is formed with the composition consisting of 15-60wt% high polymer materials, 35-80wt% spherical inorganic filler of 0.5-1.0 Wadell spheroidicity, and 0-15wt% slidability giving agent. A thermoplastic resin, a thermosetting resin, or a mixture of them is used as high polymer materials. A silica, an alumina, a silicon carbide, glass beads, or the like is used as the spherical inorganic filler. A fine graphite powder or/and a fine polytetrafluoroethylene powder are used as the slidability giving agent. Thus, the tape is set and run light and smoothly.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to a tape guide for a cassette tape used in a magnetic recording/reproducing device or the like.

(b) Japanese technology Cassette tapes used in magnetic recording and reproducing devices, etc., have a feed reel and a take-up reel arranged in a case, and the tape fed out from the feed reel passes through a guide post, a tape guide, and faces a head. The tape is then wound onto a take-up reel via a tape guide and a guide post. The tape guide usually has a cylindrical shape and plays the role of accurately positioning the running tape and ensuring its smooth running.

By the way, in recent years, magnetic recording and reproducing devices have been pursued with extremely high precision, which requires strict tape running stability, and tape guides must also have high dimensional stability, low abrasion, high hardness, and high surface precision. , high slip properties are required.

As tape guides that meet these requirements, stainless steel tape guides are used, which are made of cylindrical stainless steel and are polished or plated with hard chrome to improve surface precision and hardness.

On the other hand, various attempts have been made to make tape guides from resin for the purpose of mass production, including ABS resin, polyamide resin,
Tapes molded from thermoplastic resins such as polyacetal resin or thermosetting resins such as epoxy resins are also used, or tape guides molded from these resins mixed with fillers are also used.

(e) Problems to be solved by the invention However, although the stainless steel tape guide described above is satisfactory in terms of quality, it requires polishing and hard chrome plating, resulting in poor productivity and high cost. If these stainless steel tape guides come into contact with each other, the tape guide surface will be scratched and the running tape may be damaged, and the playback signal may become distorted, so be careful when handling stainless steel tape guides. Disadvantages include the fact that they cannot be packaged in bulk and each piece must be packaged separately.

On the other hand, tape guides made of resin have the advantage of being able to be packaged in bulk, but in the case of thermoplastic resin, the heat generated by the sliding resistance with the tape causes dimensional changes and a decrease in hardness, making the tape running unstable. Thermosetting resins have good dimensional stability, abrasion resistance, and hardness, but the slipperiness is not always sufficient and there is the problem of damaging the tape. It is not as reliable as the stainless steel tape guide mentioned above,
As a result, there was a restriction that it could not be used as a tape guide for high-quality tape cassettes.

(d) Means for Solving the Problems The present invention was made as a result of extensive research in order to provide a tape guide whose quality is comparable to stainless steel tape guides even though it is a resin molded product. .

That is, the tape guide for a cassette tape of the present invention comprises: 15 to 60 1% by weight of a polymer material, and a spherical inorganic filler with a Wardell sphericity of 0.5 to 1.0.
It is characterized by being molded from a composition consisting of 35 to 80% by weight, and 0 to 15% by weight of a sliding properties imparting agent, and thus a spherical inorganic filler having a specific sphericity in a polymeric material. By blending a specific amount of the agent and molding it, a tape guide that solves the above problems has been obtained.

The tape guide for cassette tape of the present invention will be explained in detail below.

The polymer material in the present invention refers to a thermoplastic resin (A), a thermosetting resin (B), or a polymer alloy obtained by mixing the (A) and (B).

The above (A) includes, for example, polyacetal resin, polysulfone resin, polyamide resin, ABS resin, polycarbonate resin, thermoplastic polyester resin, polyetherimide resin, polyether ether ketone I [I,
Examples include polyphenylene oxide resin and polyphenylene sulfide resin.

Examples of the above-mentioned CB) include epoxy resins, unsaturated polyester resins, phenol resins, noaryl heptatarate resins, urea resins, guanamine resins, and melamine resins.

Furthermore, as the spherical inorganic filler, among particles of silica, alumina, silicon carbide, 〃Russ beads, etc., particles having a Wardell sphericity of 0.5 to 1.0 are used, but the particle size is not particularly limited. In order to maintain the surface smoothness of the resulting tape guide, it is preferable to select from the range of 40 μm or less, especially from 0.1 to 30 μm. If the value is less than 0.5, the sliding properties during tape running are not necessarily sufficient, and the quality is not satisfactory.

Here, Wardell's sphericity is an index that measures the sphericity of a particle by (the diameter of the smallest circle circumscribing the projected image of the particle), and the closer this index is to 1.0, the closer the particle is to a true sphere. means. (Refer to "Chemical Engineering Handbook" published by Maruzen Co., Ltd.) Next, as the sliding property imparting agent, graphite fine powder and polytetrafluoroethylene fine powder are used, and it is also preferable to use both of them together.

Among the above, the polymeric material and the spherical inorganic filler having a sphericity of 0.5 to 1.0 are essential components, and the slidability imparting agent is an optional component.

The blending ratio of each component is, assuming that the total amount of the composition is 100% by weight, the polymer material is 15 to 60% by weight, and the spherical inorganic filler with a Wardell sphericity of 0.5 to 1.0 is 35 to 80% by weight. % by weight, selected so that the sliding property imparting agent is 0 to 15% by weight.
Ru.

Too little polymeric material and too much spherical inorganic filler are inappropriate because the resulting tape guide will lack mechanical strength; on the other hand, too much polymeric material and too little spherical inorganic filler are inappropriate. The desired improvement effect cannot be obtained in α of wear resistance, hardness, surface precision, and slipperiness. There is no problem even if the sliding property imparting agent is not used, but if it is used in an amount of 15% by weight or less based on the total amount of the composition, it will improve the sliding property without impairing the mechanical strength.
This is preferable because the sliding properties can be further improved.

In addition, when the sliding property imparting agent is fine graphite powder;
Another advantage is that the surface electrical resistance of the resulting tape guide can be reduced.

The optimum range of the blending ratio of each component above is that the polymer material is 15%
50 to 50% by weight, 50 to 80% by weight of the spherical p&machine filler having the above-mentioned sphericity of 0°5 to 1°O, and 2 to 15% by weight of the sliding properties imparting agent.

A small amount of known molding additives such as a stabilizer, a mold release agent, a coloring agent, a viscosity modifier, etc. can be further added to the composition containing the above-mentioned components.

By mixing the above components, preforming as the case may be to form pellets, tablets, etc., and then molding by a molding method such as compression molding, trans77 molding, injection molding, etc., the target tape guide can be obtained. It will be done.

The shape of the tape guide is often cylindrical, but it can also be bobbin-shaped or cylindrical.

(e) Function When the tape guide of the present invention is installed on a cassette tape and the tape is run, a part of the spherical inorganic filler, which is close to a perfect sphere, is exposed on the tape guide surface, so the tape comes into contact with the microscopic convex surface. while running smoothly. In particular, if the tape guide is formed by adding a sliding property agent such as graphite or polytetrafluoroethylene fine powder, which has good sliding properties, the sliding resistance will be further reduced by 7F, so the tape will run better. becomes even smoother.

(f) Examples Next, the present invention will be further explained with reference to examples. below"%
” indicates a weight of 1%.

Example 1 25% thermosetting epoxy resin as polymer material, average particle size 16 μm as spherical inorganic filler, Wardell sphericity 0
．． Using 75% of amorphous silica powder of No. 7, a molding composition was obtained by kneading them with rolls, and this composition was filled into a mold and heated and hardened at 150° C. under pressure to form the mold, and the inner diameter was 4.
．． A tape guide having dimensions of 8InIIl, outer diameter 6.0 am, height 1G, and Omm was obtained.

The results are shown in Table 1.

Comparative Example 1 A tape guide was obtained by performing the same molding as in Example 1 using only epoxy resin. The results are also shown in Table 11.

Comparative Example 2 A tape guide was obtained by molding under the same conditions as in Example 1, except that ordinary commercially available amorphous silica powder (average particle size: 16 μm) was used as a free filler.

The results are shown in Table tIIi1.

Note that the friction coefficient in the table is an average value of 10 samples.

Table 1: Running stability: A videotape is run at high speed and its running stability is determined.

Example 2 27% thermosetting epoxy resin as polymer material, average particle size 1θμ theory as spherical inorganic filler, Wardell sphericity 0
．． Using 64% of amorphous silica powder of No. 7 and 9% of graphite as a sliding property imparting agent, these were kneaded with a roll to obtain a molding composition, and molded in the same manner as in Example 1.
Got a tape guide.

Example 3 28% thermosetting epoxy resin as the polymer material, 66% amorphous silica powder with an average particle size of 16μ11 and Wardell's sphericity of 0.7 as the spherical inorganic filler, and 1μ brocade powder with a particle size of 1μ as the slidability imparting agent. Bolite) Lafluoroethylene fine powder 6%
These were roll-kneaded to obtain a molding composition, and then molded in the same manner as in Example 1 to obtain a tape guide.

Example 4 27% thermosetting epoxy resin as polymer material, spherical p
64% amorphous silica powder with an average particle size of 16μ theory and near Wardell sphericity was used as a machine filler, 6% graphite as a sliding property imparting agent, and 3% polytetrafluoroethylene fine powder with a particle size of 1μ theory. These were roll-kneaded to obtain a molding composition, which was then molded in the same manner as in Example 1 to obtain a tape guide.

The results of Examples 2 to 4 are shown in Table 2.

Table 2 Example 5 Polyacetal resin 30% as polymer material, average particle size 16 μm as spherical inorganic filler, Wardell sphericity 0.
Using 70% of the amorphous silica powder of No. 7, they were mixed and pelletized using an extruder. Then, the pellets were fed to an injection molding machine and injection molded at a temperature of 200°C to form a mold with an inner diameter of 4.8 mm and an outer diameter of 6 mm. , Ol1ls height 16. Omm
A tape guide with + dimensions was obtained.

The results are shown in Table 3.

Comparative Example 3 A tape guide was obtained by injection molding in the same manner as in Example 5 using only polyacetal resin. The results are also shown in Table 3.

Comparative Example 4 A tape guide was obtained by injection molding under the same conditions as in Example 5, except that ordinary commercially available amorphous silica powder (average particle size: 16 μm) was used as a p&machine filler. The results are also shown in Table 3.

Table 3 Example 6 27% polyamide resin as the polymer material, 16 μm average particle size noodles as the spherical *m filler, 64% amorphous silica powder with Wardell sphericity of 0.7, and the graph as the sliding property imparting agent. Using 9% phyto, injection molding was performed in the same manner as in Example 5 to obtain a tape guide.

Example 7 28% polyamide resin as the polymer material, 66% amorphous silica powder with an average particle size of 1θμ- and Wardell's sphericity of 0.7 as the spherical inorganic filler, and 66% of amorphous silica powder with a particle size of 1μ as the sliding property imparting agent. Using 6% polytetrafluoroethylene fine powder, injection molding was performed in the same manner as in Example 5 to obtain a tape guide.

Example 8 The polymer material was 27% polyacetal resin, the spherical inorganic filler had an average particle size of 16 μm, and the Wardell sphericity was 0.
Injection molding was carried out under the same conditions as in Example 5 using 64% of amorphous silica powder of No. 7, 6% of graphite as a sliding property imparting agent, and 3% of polytetrafluoroethylene fine powder with a particle size of 1 μm. I went and got a tape guide.

The results of Examples 6 to 8 are shown in Table 4 below.

(Margins below) Table 4 (g) Effects of the Invention In the tape guide of the present invention, a microscopic convex surface is formed on the surface by the added spherical inorganic filler, so the tape does not come into contact with the convex surface. As a result, the tape runs smoothly without being scratched when sliding, with extremely little wear and less frictional heat generation. In particular, when a sliding property imparting agent such as graphite or polytetrafluoroethylene fine powder, which has good sliding properties and sliding properties, is added, the sliding resistance can be further reduced and the running performance can be further improved.

Therefore, although the tape guide of the present invention is made of resin, it has properties comparable to those of stainless steel tape guides with hard chrome plating, which are said to have excellent weight, are lightweight, and can be used all at once. Packaging is also possible, making it easy to automate the installation process.

In addition, the blending of spherical inorganic fillers improves the flow of the resin during molding, and especially when thermosetting resins are used, it improves the releasability from the mold after molding and hardening, and reduces mold wear. , it is possible to stably mass-produce high-precision molded products.

Claims (2)

[Claims] (1) From a composition consisting of 15 to 60% by weight of a polymeric material, 35 to 80% by weight of a spherical inorganic filler with a Wardell sphericity of 0.5 to 1.0, and 0 to 15% by weight of a sliding property imparting agent. Tape guide for formed cassette tapes. (2) The tape guide for a cassette tape according to claim 1, wherein the sliding properties imparting agent is a fine graphite powder or/and a fine polytetrafluoroethylene powder.